Origin of Solar System

The Origin of the Solar System One of the most intriguing questions in astronomy today is the how our solar system formed. Not only does the answer add insight to other similarly forming systems, but also helps to satisfy our curiosity about the origin of our species. Although it is highly unlikely that astronomers will ever know with absolute scientific certainty how our system originated, they can construct similar theoretical models with the hopes gaining a better understanding. A basic understand of the current physical aspects of our solar system are helpful when trying to analyzing its origin. Our solar system is made of the Sun, nine major planets, at least sixty planetary satellite, thousands of asteroids and comets that all span an immense distance. Each planet has its own individual characteristics and seven of which have one or more satellites. There are thousands of asteroids, mainly congested in the area between Mars and Jupiter, as well as countless comets that all travel in a spherical orbit around our Sun. The Sun contains approximately 99 percent of the mass in the solar system, but only 2 percent of the system’s angular momentum. It lies in the center of our system while all planets, asteroids and alike rotate in elliptical orbits around it in the same plane. The smaller inner planets have solid surfaces, lack ring systems and have far fewer satellites then the outer planets. Atmospheres of most of the inner planets consist of large quantities of oxidized compounds such as carbon dioxide. While on the other hand, the outer planets are far more massive then the inner terrestrial planets, and have gigantic atmospheres composed mainly of hydrogen and helium. Asteroids and comets make up the smallest portion of the solar systems entities and are composed of the remnants left behind while planets were forming. For over 300 years, there has been a very long history of conjecture on the origin of the solar system. These many theories stem from two general categories. The first category called monistic, involves the evolution of the Sun and planets as an isolated system. The second group of theories called dualistic, suggested that the solar system formed as a result of the interaction between two individual stars. The dualistic formation theory has been almost entirely dropped and monistic formation has become the general consensus on the basic formation of our solar system. Most modern theories of the origin of the solar system hypothesize that all bodies in the solar system, including the sun accreted from the formation and evolution of a single primordial solar nebula. It is believed that our solar system began to form around 4.56 billion years ago from a dense interstellar cloud of gas. Because of the conservation of angular momentum, the cloud of gas formed a rotating flattened disk approximately the size of the planetary system. It was this flattened disk that is referred to as the primitive solar nebula and from which our current solar system evolved. Ordinarily, the internal pressures of the cloud are sufficient to prevent if form collapsing. However, from time to time local increases in pressure of the interstellar medium cause the additional compression of interstellar clouds. These compressions caused the clouds to reach their threshold of gravitational collapse. Once the gravitational attraction of matter is greater then any tendency to expand due to internal pressures the cloud begins to collapse inward. Theoretical models suggest that the presolar nebula continued to collapse until the center of the cloud became so dense that heat started to form. This heat increased the thermal pressure of the cloud until the collapse was eventually halted. The existence of our system of planets is entirely due to the angular momentum of the initial cloud. If there were no angular momentum, then the interstellar cloud would have collapsed to from a single star. While at the same time, if the collapse had occurred under a system with too much angular momentum then a binary star would have resulted from our system. Our system formed under intermediate conditions allowing the planets to evolve. The fact that the Sun contains 99 percent of the solar system’s mass but only 2 percent of its angular momentum raises questions about the distribution of masses